Adding upstream version 1:9.2p1.upstream/1%9.2p1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 872 insertions, 0 deletions

diff --git a/ssh-keyscan.c b/ssh-keyscan.c
new file mode 100644
index 0000000..1318c2f
--- /dev/null
+++ b/ssh-keyscan.c
@@ -0,0 +1,872 @@
+/* $OpenBSD: ssh-keyscan.c,v 1.149 2022/12/26 19:16:03 jmc Exp $ */
+/*
+ * Copyright 1995, 1996 by David Mazieres <dm@lcs.mit.edu>.
+ *
+ * Modification and redistribution in source and binary forms is
+ * permitted provided that due credit is given to the author and the
+ * OpenBSD project by leaving this copyright notice intact.
+ */
+
+#include "includes.h"
+ 
+#include <sys/types.h>
+#include "openbsd-compat/sys-queue.h"
+#include <sys/resource.h>
+#ifdef HAVE_SYS_TIME_H
+# include <sys/time.h>
+#endif
+
+#include <netinet/in.h>
+#include <arpa/inet.h>
+
+#ifdef WITH_OPENSSL
+#include <openssl/bn.h>
+#endif
+
+#include <netdb.h>
+#include <errno.h>
+#ifdef HAVE_POLL_H
+#include <poll.h>
+#endif
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "xmalloc.h"
+#include "ssh.h"
+#include "sshbuf.h"
+#include "sshkey.h"
+#include "cipher.h"
+#include "kex.h"
+#include "compat.h"
+#include "myproposal.h"
+#include "packet.h"
+#include "dispatch.h"
+#include "log.h"
+#include "atomicio.h"
+#include "misc.h"
+#include "hostfile.h"
+#include "ssherr.h"
+#include "ssh_api.h"
+#include "dns.h"
+#include "addr.h"
+
+/* Flag indicating whether IPv4 or IPv6.  This can be set on the command line.
+   Default value is AF_UNSPEC means both IPv4 and IPv6. */
+int IPv4or6 = AF_UNSPEC;
+
+int ssh_port = SSH_DEFAULT_PORT;
+
+#define KT_DSA		(1)
+#define KT_RSA		(1<<1)
+#define KT_ECDSA	(1<<2)
+#define KT_ED25519	(1<<3)
+#define KT_XMSS		(1<<4)
+#define KT_ECDSA_SK	(1<<5)
+#define KT_ED25519_SK	(1<<6)
+
+#define KT_MIN		KT_DSA
+#define KT_MAX		KT_ED25519_SK
+
+int get_cert = 0;
+int get_keytypes = KT_RSA|KT_ECDSA|KT_ED25519|KT_ECDSA_SK|KT_ED25519_SK;
+
+int hash_hosts = 0;		/* Hash hostname on output */
+
+int print_sshfp = 0;		/* Print SSHFP records instead of known_hosts */
+
+int found_one = 0;		/* Successfully found a key */
+
+#define MAXMAXFD 256
+
+/* The number of seconds after which to give up on a TCP connection */
+int timeout = 5;
+
+int maxfd;
+#define MAXCON (maxfd - 10)
+
+extern char *__progname;
+struct pollfd *read_wait;
+int ncon;
+
+/*
+ * Keep a connection structure for each file descriptor.  The state
+ * associated with file descriptor n is held in fdcon[n].
+ */
+typedef struct Connection {
+	u_char c_status;	/* State of connection on this file desc. */
+#define CS_UNUSED 0		/* File descriptor unused */
+#define CS_CON 1		/* Waiting to connect/read greeting */
+#define CS_SIZE 2		/* Waiting to read initial packet size */
+#define CS_KEYS 3		/* Waiting to read public key packet */
+	int c_fd;		/* Quick lookup: c->c_fd == c - fdcon */
+	int c_plen;		/* Packet length field for ssh packet */
+	int c_len;		/* Total bytes which must be read. */
+	int c_off;		/* Length of data read so far. */
+	int c_keytype;		/* Only one of KT_* */
+	sig_atomic_t c_done;	/* SSH2 done */
+	char *c_namebase;	/* Address to free for c_name and c_namelist */
+	char *c_name;		/* Hostname of connection for errors */
+	char *c_namelist;	/* Pointer to other possible addresses */
+	char *c_output_name;	/* Hostname of connection for output */
+	char *c_data;		/* Data read from this fd */
+	struct ssh *c_ssh;	/* SSH-connection */
+	struct timespec c_ts;	/* Time at which connection gets aborted */
+	TAILQ_ENTRY(Connection) c_link;	/* List of connections in timeout order. */
+} con;
+
+TAILQ_HEAD(conlist, Connection) tq;	/* Timeout Queue */
+con *fdcon;
+
+static void keyprint(con *c, struct sshkey *key);
+
+static int
+fdlim_get(int hard)
+{
+#if defined(HAVE_GETRLIMIT) && defined(RLIMIT_NOFILE)
+	struct rlimit rlfd;
+
+	if (getrlimit(RLIMIT_NOFILE, &rlfd) == -1)
+		return (-1);
+	if ((hard ? rlfd.rlim_max : rlfd.rlim_cur) == RLIM_INFINITY)
+		return SSH_SYSFDMAX;
+	else
+		return hard ? rlfd.rlim_max : rlfd.rlim_cur;
+#else
+	return SSH_SYSFDMAX;
+#endif
+}
+
+static int
+fdlim_set(int lim)
+{
+#if defined(HAVE_SETRLIMIT) && defined(RLIMIT_NOFILE)
+	struct rlimit rlfd;
+#endif
+
+	if (lim <= 0)
+		return (-1);
+#if defined(HAVE_SETRLIMIT) && defined(RLIMIT_NOFILE)
+	if (getrlimit(RLIMIT_NOFILE, &rlfd) == -1)
+		return (-1);
+	rlfd.rlim_cur = lim;
+	if (setrlimit(RLIMIT_NOFILE, &rlfd) == -1)
+		return (-1);
+#elif defined (HAVE_SETDTABLESIZE)
+	setdtablesize(lim);
+#endif
+	return (0);
+}
+
+/*
+ * This is an strsep function that returns a null field for adjacent
+ * separators.  This is the same as the 4.4BSD strsep, but different from the
+ * one in the GNU libc.
+ */
+static char *
+xstrsep(char **str, const char *delim)
+{
+	char *s, *e;
+
+	if (!**str)
+		return (NULL);
+
+	s = *str;
+	e = s + strcspn(s, delim);
+
+	if (*e != '\0')
+		*e++ = '\0';
+	*str = e;
+
+	return (s);
+}
+
+/*
+ * Get the next non-null token (like GNU strsep).  Strsep() will return a
+ * null token for two adjacent separators, so we may have to loop.
+ */
+static char *
+strnnsep(char **stringp, char *delim)
+{
+	char *tok;
+
+	do {
+		tok = xstrsep(stringp, delim);
+	} while (tok && *tok == '\0');
+	return (tok);
+}
+
+
+static int
+key_print_wrapper(struct sshkey *hostkey, struct ssh *ssh)
+{
+	con *c;
+
+	if ((c = ssh_get_app_data(ssh)) != NULL)
+		keyprint(c, hostkey);
+	/* always abort key exchange */
+	return -1;
+}
+
+static int
+ssh2_capable(int remote_major, int remote_minor)
+{
+	switch (remote_major) {
+	case 1:
+		if (remote_minor == 99)
+			return 1;
+		break;
+	case 2:
+		return 1;
+	default:
+		break;
+	}
+	return 0;
+}
+
+static void
+keygrab_ssh2(con *c)
+{
+	char *myproposal[PROPOSAL_MAX] = { KEX_CLIENT };
+	int r;
+
+	switch (c->c_keytype) {
+	case KT_DSA:
+		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
+		    "ssh-dss-cert-v01@openssh.com" : "ssh-dss";
+		break;
+	case KT_RSA:
+		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
+		    "rsa-sha2-512-cert-v01@openssh.com,"
+		    "rsa-sha2-256-cert-v01@openssh.com,"
+		    "ssh-rsa-cert-v01@openssh.com" :
+		    "rsa-sha2-512,"
+		    "rsa-sha2-256,"
+		    "ssh-rsa";
+		break;
+	case KT_ED25519:
+		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
+		    "ssh-ed25519-cert-v01@openssh.com" : "ssh-ed25519";
+		break;
+	case KT_XMSS:
+		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
+		    "ssh-xmss-cert-v01@openssh.com" : "ssh-xmss@openssh.com";
+		break;
+	case KT_ECDSA:
+		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
+		    "ecdsa-sha2-nistp256-cert-v01@openssh.com,"
+		    "ecdsa-sha2-nistp384-cert-v01@openssh.com,"
+		    "ecdsa-sha2-nistp521-cert-v01@openssh.com" :
+		    "ecdsa-sha2-nistp256,"
+		    "ecdsa-sha2-nistp384,"
+		    "ecdsa-sha2-nistp521";
+		break;
+	case KT_ECDSA_SK:
+		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
+		    "sk-ecdsa-sha2-nistp256-cert-v01@openssh.com" :
+		    "sk-ecdsa-sha2-nistp256@openssh.com";
+		break;
+	case KT_ED25519_SK:
+		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
+		    "sk-ssh-ed25519-cert-v01@openssh.com" :
+		    "sk-ssh-ed25519@openssh.com";
+		break;
+	default:
+		fatal("unknown key type %d", c->c_keytype);
+		break;
+	}
+	if ((r = kex_setup(c->c_ssh, myproposal)) != 0) {
+		free(c->c_ssh);
+		fprintf(stderr, "kex_setup: %s\n", ssh_err(r));
+		exit(1);
+	}
+#ifdef WITH_OPENSSL
+	c->c_ssh->kex->kex[KEX_DH_GRP1_SHA1] = kex_gen_client;
+	c->c_ssh->kex->kex[KEX_DH_GRP14_SHA1] = kex_gen_client;
+	c->c_ssh->kex->kex[KEX_DH_GRP14_SHA256] = kex_gen_client;
+	c->c_ssh->kex->kex[KEX_DH_GRP16_SHA512] = kex_gen_client;
+	c->c_ssh->kex->kex[KEX_DH_GRP18_SHA512] = kex_gen_client;
+	c->c_ssh->kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
+	c->c_ssh->kex->kex[KEX_DH_GEX_SHA256] = kexgex_client;
+# ifdef OPENSSL_HAS_ECC
+	c->c_ssh->kex->kex[KEX_ECDH_SHA2] = kex_gen_client;
+# endif
+#endif
+	c->c_ssh->kex->kex[KEX_C25519_SHA256] = kex_gen_client;
+	c->c_ssh->kex->kex[KEX_KEM_SNTRUP761X25519_SHA512] = kex_gen_client;
+	ssh_set_verify_host_key_callback(c->c_ssh, key_print_wrapper);
+	/*
+	 * do the key-exchange until an error occurs or until
+	 * the key_print_wrapper() callback sets c_done.
+	 */
+	ssh_dispatch_run(c->c_ssh, DISPATCH_BLOCK, &c->c_done);
+}
+
+static void
+keyprint_one(const char *host, struct sshkey *key)
+{
+	char *hostport = NULL, *hashed = NULL;
+	const char *known_host;
+
+	found_one = 1;
+
+	if (print_sshfp) {
+		export_dns_rr(host, key, stdout, 0);
+		return;
+	}
+
+	hostport = put_host_port(host, ssh_port);
+	lowercase(hostport);
+	if (hash_hosts && (hashed = host_hash(hostport, NULL, 0)) == NULL)
+		fatal("host_hash failed");
+	known_host = hash_hosts ? hashed : hostport;
+	if (!get_cert)
+		fprintf(stdout, "%s ", known_host);
+	sshkey_write(key, stdout);
+	fputs("\n", stdout);
+	free(hashed);
+	free(hostport);
+}
+
+static void
+keyprint(con *c, struct sshkey *key)
+{
+	char *hosts = c->c_output_name ? c->c_output_name : c->c_name;
+	char *host, *ohosts;
+
+	if (key == NULL)
+		return;
+	if (get_cert || (!hash_hosts && ssh_port == SSH_DEFAULT_PORT)) {
+		keyprint_one(hosts, key);
+		return;
+	}
+	ohosts = hosts = xstrdup(hosts);
+	while ((host = strsep(&hosts, ",")) != NULL)
+		keyprint_one(host, key);
+	free(ohosts);
+}
+
+static int
+tcpconnect(char *host)
+{
+	struct addrinfo hints, *ai, *aitop;
+	char strport[NI_MAXSERV];
+	int gaierr, s = -1;
+
+	snprintf(strport, sizeof strport, "%d", ssh_port);
+	memset(&hints, 0, sizeof(hints));
+	hints.ai_family = IPv4or6;
+	hints.ai_socktype = SOCK_STREAM;
+	if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
+		error("getaddrinfo %s: %s", host, ssh_gai_strerror(gaierr));
+		return -1;
+	}
+	for (ai = aitop; ai; ai = ai->ai_next) {
+		s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
+		if (s == -1) {
+			error("socket: %s", strerror(errno));
+			continue;
+		}
+		if (set_nonblock(s) == -1)
+			fatal_f("set_nonblock(%d)", s);
+		if (connect(s, ai->ai_addr, ai->ai_addrlen) == -1 &&
+		    errno != EINPROGRESS)
+			error("connect (`%s'): %s", host, strerror(errno));
+		else
+			break;
+		close(s);
+		s = -1;
+	}
+	freeaddrinfo(aitop);
+	return s;
+}
+
+static int
+conalloc(const char *iname, const char *oname, int keytype)
+{
+	char *namebase, *name, *namelist;
+	int s;
+
+	namebase = namelist = xstrdup(iname);
+
+	do {
+		name = xstrsep(&namelist, ",");
+		if (!name) {
+			free(namebase);
+			return (-1);
+		}
+	} while ((s = tcpconnect(name)) < 0);
+
+	if (s >= maxfd)
+		fatal("conalloc: fdno %d too high", s);
+	if (fdcon[s].c_status)
+		fatal("conalloc: attempt to reuse fdno %d", s);
+
+	debug3_f("oname %s kt %d", oname, keytype);
+	fdcon[s].c_fd = s;
+	fdcon[s].c_status = CS_CON;
+	fdcon[s].c_namebase = namebase;
+	fdcon[s].c_name = name;
+	fdcon[s].c_namelist = namelist;
+	fdcon[s].c_output_name = xstrdup(oname);
+	fdcon[s].c_data = (char *) &fdcon[s].c_plen;
+	fdcon[s].c_len = 4;
+	fdcon[s].c_off = 0;
+	fdcon[s].c_keytype = keytype;
+	monotime_ts(&fdcon[s].c_ts);
+	fdcon[s].c_ts.tv_sec += timeout;
+	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
+	read_wait[s].fd = s;
+	read_wait[s].events = POLLIN;
+	ncon++;
+	return (s);
+}
+
+static void
+confree(int s)
+{
+	if (s >= maxfd || fdcon[s].c_status == CS_UNUSED)
+		fatal("confree: attempt to free bad fdno %d", s);
+	free(fdcon[s].c_namebase);
+	free(fdcon[s].c_output_name);
+	if (fdcon[s].c_status == CS_KEYS)
+		free(fdcon[s].c_data);
+	fdcon[s].c_status = CS_UNUSED;
+	fdcon[s].c_keytype = 0;
+	if (fdcon[s].c_ssh) {
+		ssh_packet_close(fdcon[s].c_ssh);
+		free(fdcon[s].c_ssh);
+		fdcon[s].c_ssh = NULL;
+	} else
+		close(s);
+	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
+	read_wait[s].fd = -1;
+	read_wait[s].events = 0;
+	ncon--;
+}
+
+static void
+contouch(int s)
+{
+	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
+	monotime_ts(&fdcon[s].c_ts);
+	fdcon[s].c_ts.tv_sec += timeout;
+	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
+}
+
+static int
+conrecycle(int s)
+{
+	con *c = &fdcon[s];
+	int ret;
+
+	ret = conalloc(c->c_namelist, c->c_output_name, c->c_keytype);
+	confree(s);
+	return (ret);
+}
+
+static void
+congreet(int s)
+{
+	int n = 0, remote_major = 0, remote_minor = 0;
+	char buf[256], *cp;
+	char remote_version[sizeof buf];
+	size_t bufsiz;
+	con *c = &fdcon[s];
+
+	/* send client banner */
+	n = snprintf(buf, sizeof buf, "SSH-%d.%d-OpenSSH-keyscan\r\n",
+	    PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2);
+	if (n < 0 || (size_t)n >= sizeof(buf)) {
+		error("snprintf: buffer too small");
+		confree(s);
+		return;
+	}
+	if (atomicio(vwrite, s, buf, n) != (size_t)n) {
+		error("write (%s): %s", c->c_name, strerror(errno));
+		confree(s);
+		return;
+	}
+
+	/*
+	 * Read the server banner as per RFC4253 section 4.2.  The "SSH-"
+	 * protocol identification string may be preceeded by an arbitrarily
+	 * large banner which we must read and ignore.  Loop while reading
+	 * newline-terminated lines until we have one starting with "SSH-".
+	 * The ID string cannot be longer than 255 characters although the
+	 * preceeding banner lines may (in which case they'll be discarded
+	 * in multiple iterations of the outer loop).
+	 */
+	for (;;) {
+		memset(buf, '\0', sizeof(buf));
+		bufsiz = sizeof(buf);
+		cp = buf;
+		while (bufsiz-- &&
+		    (n = atomicio(read, s, cp, 1)) == 1 && *cp != '\n') {
+			if (*cp == '\r')
+				*cp = '\n';
+			cp++;
+		}
+		if (n != 1 || strncmp(buf, "SSH-", 4) == 0)
+			break;
+	}
+	if (n == 0) {
+		switch (errno) {
+		case EPIPE:
+			error("%s: Connection closed by remote host", c->c_name);
+			break;
+		case ECONNREFUSED:
+			break;
+		default:
+			error("read (%s): %s", c->c_name, strerror(errno));
+			break;
+		}
+		conrecycle(s);
+		return;
+	}
+	if (cp >= buf + sizeof(buf)) {
+		error("%s: greeting exceeds allowable length", c->c_name);
+		confree(s);
+		return;
+	}
+	if (*cp != '\n' && *cp != '\r') {
+		error("%s: bad greeting", c->c_name);
+		confree(s);
+		return;
+	}
+	*cp = '\0';
+	if ((c->c_ssh = ssh_packet_set_connection(NULL, s, s)) == NULL)
+		fatal("ssh_packet_set_connection failed");
+	ssh_packet_set_timeout(c->c_ssh, timeout, 1);
+	ssh_set_app_data(c->c_ssh, c);	/* back link */
+	c->c_ssh->compat = 0;
+	if (sscanf(buf, "SSH-%d.%d-%[^\n]\n",
+	    &remote_major, &remote_minor, remote_version) == 3)
+		compat_banner(c->c_ssh, remote_version);
+	if (!ssh2_capable(remote_major, remote_minor)) {
+		debug("%s doesn't support ssh2", c->c_name);
+		confree(s);
+		return;
+	}
+	fprintf(stderr, "%c %s:%d %s\n", print_sshfp ? ';' : '#',
+	    c->c_name, ssh_port, chop(buf));
+	keygrab_ssh2(c);
+	confree(s);
+}
+
+static void
+conread(int s)
+{
+	con *c = &fdcon[s];
+	size_t n;
+
+	if (c->c_status == CS_CON) {
+		congreet(s);
+		return;
+	}
+	n = atomicio(read, s, c->c_data + c->c_off, c->c_len - c->c_off);
+	if (n == 0) {
+		error("read (%s): %s", c->c_name, strerror(errno));
+		confree(s);
+		return;
+	}
+	c->c_off += n;
+
+	if (c->c_off == c->c_len)
+		switch (c->c_status) {
+		case CS_SIZE:
+			c->c_plen = htonl(c->c_plen);
+			c->c_len = c->c_plen + 8 - (c->c_plen & 7);
+			c->c_off = 0;
+			c->c_data = xmalloc(c->c_len);
+			c->c_status = CS_KEYS;
+			break;
+		default:
+			fatal("conread: invalid status %d", c->c_status);
+			break;
+		}
+
+	contouch(s);
+}
+
+static void
+conloop(void)
+{
+	struct timespec seltime, now;
+	con *c;
+	int i;
+
+	monotime_ts(&now);
+	c = TAILQ_FIRST(&tq);
+
+	if (c && timespeccmp(&c->c_ts, &now, >))
+		timespecsub(&c->c_ts, &now, &seltime);
+	else
+		timespecclear(&seltime);
+
+	while (ppoll(read_wait, maxfd, &seltime, NULL) == -1) {
+		if (errno == EAGAIN || errno == EINTR || errno == EWOULDBLOCK)
+			continue;
+		error("poll error");
+	}
+
+	for (i = 0; i < maxfd; i++) {
+		if (read_wait[i].revents & (POLLHUP|POLLERR|POLLNVAL))
+			confree(i);
+		else if (read_wait[i].revents & (POLLIN|POLLHUP))
+			conread(i);
+	}
+
+	c = TAILQ_FIRST(&tq);
+	while (c && timespeccmp(&c->c_ts, &now, <)) {
+		int s = c->c_fd;
+
+		c = TAILQ_NEXT(c, c_link);
+		conrecycle(s);
+	}
+}
+
+static void
+do_one_host(char *host)
+{
+	char *name = strnnsep(&host, " \t\n");
+	int j;
+
+	if (name == NULL)
+		return;
+	for (j = KT_MIN; j <= KT_MAX; j *= 2) {
+		if (get_keytypes & j) {
+			while (ncon >= MAXCON)
+				conloop();
+			conalloc(name, *host ? host : name, j);
+		}
+	}
+}
+
+static void
+do_host(char *host)
+{
+	char daddr[128];
+	struct xaddr addr, end_addr;
+	u_int masklen;
+
+	if (host == NULL)
+		return;
+	if (addr_pton_cidr(host, &addr, &masklen) != 0) {
+		/* Assume argument is a hostname */
+		do_one_host(host);
+	} else {
+		/* Argument is a CIDR range */
+		debug("CIDR range %s", host);
+		end_addr = addr;
+		if (addr_host_to_all1s(&end_addr, masklen) != 0)
+			goto badaddr;
+		/*
+		 * Note: we deliberately include the all-zero/ones addresses.
+		 */
+		for (;;) {
+			if (addr_ntop(&addr, daddr, sizeof(daddr)) != 0) {
+ badaddr:
+				error("Invalid address %s", host);
+				return;
+			}
+			debug("CIDR expand: address %s", daddr);
+			do_one_host(daddr);
+			if (addr_cmp(&addr, &end_addr) == 0)
+				break;
+			addr_increment(&addr);
+		};
+	}
+}
+
+void
+sshfatal(const char *file, const char *func, int line, int showfunc,
+    LogLevel level, const char *suffix, const char *fmt, ...)
+{
+	va_list args;
+
+	va_start(args, fmt);
+	sshlogv(file, func, line, showfunc, level, suffix, fmt, args);
+	va_end(args);
+	cleanup_exit(255);
+}
+
+static void
+usage(void)
+{
+	fprintf(stderr,
+	    "usage: %s [-46cDHv] [-f file] [-p port] [-T timeout] [-t type]\n"
+	    "\t\t   [host | addrlist namelist]\n",
+	    __progname);
+	exit(1);
+}
+
+int
+main(int argc, char **argv)
+{
+	int debug_flag = 0, log_level = SYSLOG_LEVEL_INFO;
+	int opt, fopt_count = 0, j;
+	char *tname, *cp, *line = NULL;
+	size_t linesize = 0;
+	FILE *fp;
+
+	extern int optind;
+	extern char *optarg;
+
+	__progname = ssh_get_progname(argv[0]);
+	seed_rng();
+	TAILQ_INIT(&tq);
+
+	/* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
+	sanitise_stdfd();
+
+	if (argc <= 1)
+		usage();
+
+	while ((opt = getopt(argc, argv, "cDHv46p:T:t:f:")) != -1) {
+		switch (opt) {
+		case 'H':
+			hash_hosts = 1;
+			break;
+		case 'c':
+			get_cert = 1;
+			break;
+		case 'D':
+			print_sshfp = 1;
+			break;
+		case 'p':
+			ssh_port = a2port(optarg);
+			if (ssh_port <= 0) {
+				fprintf(stderr, "Bad port '%s'\n", optarg);
+				exit(1);
+			}
+			break;
+		case 'T':
+			timeout = convtime(optarg);
+			if (timeout == -1 || timeout == 0) {
+				fprintf(stderr, "Bad timeout '%s'\n", optarg);
+				usage();
+			}
+			break;
+		case 'v':
+			if (!debug_flag) {
+				debug_flag = 1;
+				log_level = SYSLOG_LEVEL_DEBUG1;
+			}
+			else if (log_level < SYSLOG_LEVEL_DEBUG3)
+				log_level++;
+			else
+				fatal("Too high debugging level.");
+			break;
+		case 'f':
+			if (strcmp(optarg, "-") == 0)
+				optarg = NULL;
+			argv[fopt_count++] = optarg;
+			break;
+		case 't':
+			get_keytypes = 0;
+			tname = strtok(optarg, ",");
+			while (tname) {
+				int type = sshkey_type_from_name(tname);
+
+				switch (type) {
+				case KEY_DSA:
+					get_keytypes |= KT_DSA;
+					break;
+				case KEY_ECDSA:
+					get_keytypes |= KT_ECDSA;
+					break;
+				case KEY_RSA:
+					get_keytypes |= KT_RSA;
+					break;
+				case KEY_ED25519:
+					get_keytypes |= KT_ED25519;
+					break;
+				case KEY_XMSS:
+					get_keytypes |= KT_XMSS;
+					break;
+				case KEY_ED25519_SK:
+					get_keytypes |= KT_ED25519_SK;
+					break;
+				case KEY_ECDSA_SK:
+					get_keytypes |= KT_ECDSA_SK;
+					break;
+				case KEY_UNSPEC:
+				default:
+					fatal("Unknown key type \"%s\"", tname);
+				}
+				tname = strtok(NULL, ",");
+			}
+			break;
+		case '4':
+			IPv4or6 = AF_INET;
+			break;
+		case '6':
+			IPv4or6 = AF_INET6;
+			break;
+		default:
+			usage();
+		}
+	}
+	if (optind == argc && !fopt_count)
+		usage();
+
+	log_init("ssh-keyscan", log_level, SYSLOG_FACILITY_USER, 1);
+
+	maxfd = fdlim_get(1);
+	if (maxfd < 0)
+		fatal("%s: fdlim_get: bad value", __progname);
+	if (maxfd > MAXMAXFD)
+		maxfd = MAXMAXFD;
+	if (MAXCON <= 0)
+		fatal("%s: not enough file descriptors", __progname);
+	if (maxfd > fdlim_get(0))
+		fdlim_set(maxfd);
+	fdcon = xcalloc(maxfd, sizeof(con));
+	read_wait = xcalloc(maxfd, sizeof(struct pollfd));
+	for (j = 0; j < maxfd; j++)
+		read_wait[j].fd = -1;
+
+	for (j = 0; j < fopt_count; j++) {
+		if (argv[j] == NULL)
+			fp = stdin;
+		else if ((fp = fopen(argv[j], "r")) == NULL)
+			fatal("%s: %s: %s", __progname, argv[j], strerror(errno));
+
+		while (getline(&line, &linesize, fp) != -1) {
+			/* Chomp off trailing whitespace and comments */
+			if ((cp = strchr(line, '#')) == NULL)
+				cp = line + strlen(line) - 1;
+			while (cp >= line) {
+				if (*cp == ' ' || *cp == '\t' ||
+				    *cp == '\n' || *cp == '#')
+					*cp-- = '\0';
+				else
+					break;
+			}
+
+			/* Skip empty lines */
+			if (*line == '\0')
+				continue;
+
+			do_host(line);
+		}
+
+		if (ferror(fp))
+			fatal("%s: %s: %s", __progname, argv[j], strerror(errno));
+
+		fclose(fp);
+	}
+	free(line);
+
+	while (optind < argc)
+		do_host(argv[optind++]);
+
+	while (ncon > 0)
+		conloop();
+
+	return found_one ? 0 : 1;
+}